The present invention relates to a rectangular shadow-mask, or aperture mask arrangement for a color television receiver cathode-ray tube, the arrangement including an aperture mask made of a thin metal sheet provided wih a peripheral flange, and a mask frame enclosed by the flange in a telescoping manner, the flange being fastened to the mask frame by means of a plurality of spot welds distributed around the periphery of the flange.
It is known that during operation of color television picture tubes, the impinging electron beams cause heating of the aperture mask, leading to expansion movements of the mask. Such movements can produce noticeable target errors and thus color impurities in the reproduced color picture.
Known aperture mask arrangements usually include the aperture mask proper, which is made of a very thin sheet of metal, e.g. steel, and which is provided with a peripheral flange, and a frame made of a thicker material which is inserted into the flange in a telescoping manner and which is fastened to the flange by spot welds.